Hi ok here is what my issue is. I have a 2006 5.9L. When I am driving it revs up to around 3000 rpm and 25 mph before it shifts. After it shifts the other gears are fine. I have no error codes popping up. I have removed the batteries to try to reset the computer. I have uninstalled the program (Bully Dog) and batteries again. Does anyone have any ideas on what else I can try?!

 

Try a front band adjust google it! Also may be the shift solenoids change them out.

 

Man i am having the same issue on my 5.9 but it seems like it's with 2nd ya know? freakin trucks man, they can haul a house away but throw temper tantrums like anything ;//

 

If you have all the gears whne it does hsift it is likely the electronic pieces causing it. I you hav enear 40k and have never done it, change the gov solenoid and transducer plus the output shaft speed sensor then check band setting.

 

I keep seeing this same problem over and over... drop the transmission pan I'll bet you 50 bucks your anchor came off due to ware of your second gear band or your second gear band broke. It isn't very hard to change but if you haven't had a transmission rebuild now is the time to do that as well.

PATC 46RE 47RE 48RE Transmissions, Performance Transmission A518, 518

I highly recommend getting a one piece band and going with a billet band strut, anchor and lever. While you're in there go ahead and upgrade your internals with billet input shaft (at a minimum), intermediate shaft and output shaft, upgrade upgrade to redline clutches and kolene steels, get a super servo, billet planetary, don't forget your governor solenoid and transducer and DO NOT go cheap on your converter... I'm sure there are lists upon lists of reasons to or not to get a certain converter but personally ATS 5 star converter is where it's at..... the more that I think about this and keep listing off the top of my head the more i'm realizing IF YOU HAVE NEVER DONE THIS BEFORE GET A HOLD OF A SHOP. The guys at PATC 46RE 47RE 48RE Transmissions, Performance Transmission A518, 518
will get you everything you need to do it but I've heard great things about Dog House Diesel and I'm sure they will be able to walk you through whatever you need, and probably provide you with a kit Doghouse Diesel Performance

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sorry if that is confusing ... first thing you need to do is drop your transmission pan and see if you have any lose parts sliding around in the pan.